My experience with angels is that if you can feed them a goodly amount of live food they will grow faster. With live or frozen, the amount has to be much greater because of the moisture content difference, which is close to 90% in live and frozen, and perhaps 10% or less in prepared foods. fat is a necessary ingredient in foods for breeding fish because of the high fat content of eggs.
things like fatty livers and such are not caused by fat in the diet, but rather by digestible carbohydrates. this was not an issue with steam processes to produce pellets, but is in modern extrusion techniques. to me, and I had this discussion with a vet with regard to prepared dog foods, more important than the nutritional analysis, is the list of ingredients. If wheat is the first ingredient in a food for a carnivore, (saw this on a Hikari pack) it probably isn't a good food. Fish meal is a common staple in fish foods, but there is a huge difference between grades and types. If you look at farmed salmon, which are fed a "nutritionally balanced" diet of pellets, their fitness as food for humans is questionable and they don't compare to their wild caught relatives for food value/health benefits, to humans. Why? The reason is that the commercial foods contain a fair amount of grains and what is missing is the items salmon naturally get from their diet in the wild, and as a result the farmed salmon don't have the essential Omega acids that are a health benefit to humans.
Foods need to have a certain mix of amino acids and their source isn't important, as they are the building blocks. Fish foods, generally, are a mix of items that contain these essential amino acids as well as other amino acids that may not be used by the fish. Clearly, a quality food will have good sources for the aminos we want to feed. The ingredient list will tell you more about this than the nutritional analysis will. Keep in mind that commercial foods need to be produce at a profit and competition will force the various companies to look at cost cutting measures at all times. Much of this info comes from a presentation on fish nutrition, given at our club, by a rep for a company that has made food for aquaculture for more than 80 years. The info he presented was mostly of a scientific nature, as they don't make tropical fish food. He did formulate a Koi and Goldfish pellet food, which is great for cichlids, which he keeps.
Read the labels.
As far as feeding angels, if you look at what Angels Plus feeds their fish, and they breed and sell exceptionally fine fish, using a reasonably priced food.
NLS is a great food, albeit pricey, even when buying in quantity.